kill vm if saving config failed in v3 protocol

If virDomainSaveConfig() failed, we will return NULL to source,
and the vm is still available to restart during confirm() step in
v3 protocol. So we should kill it off in qemuMigrationFinish().

In v2 protocol, we should not set vm to NULL, because we hold
a reference of vm and should unrefernce it.

src/qemu/qemu_migration.c

@@ -2471,7 +2471,7 @@ qemuMigrationFinish(struct qemud_driver *driver,
         if (!virDomainObjIsActive(vm)) {
             qemuReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                             _("guest unexpectedly quit"));
-            goto cleanup;
+            goto endjob;
         }
 
         qemuMigrationVPAssociatePortProfiles(vm->def);
@@ -2491,7 +2491,24 @@ qemuMigrationFinish(struct qemud_driver *driver,
                  * Return a NULL dom pointer, and hope that this is a rare
                  * situation and management tools are smart.
                  */
-                vm = NULL;
+
+                /*
+                 * In v3 protocol, the source VM is still available to
+                 * restart during confirm() step, so we kill it off
+                 * now.
+                 * In v2 protocol, the source is dead, so we leave
+                 * target in paused state, in case admin can fix
+                 * things up
+                 */
+                if (v3proto) {
+                    qemuProcessStop(driver, vm, 1, VIR_DOMAIN_SHUTOFF_FAILED);
+                    qemuAuditDomainStop(vm, "failed");
+                    if (newVM) {
+                        if (qemuDomainObjEndJob(vm) > 0)
+                            virDomainRemoveInactive(&driver->domains, vm);
+                        vm = NULL;
+                    }
+                }
                 goto endjob;
             }